The above named air conditioning systems are known in principle and are used in particular in vehicles for the cooling of the vehicle cabin. The refrigerant circuit of these air conditioning systems is filled with a refrigerant, for example with R 134a (previously also R 12).
In air conditioning systems of this kind there is the problem that refrigerant must be added from time to time, since there is the danger when the level is low that the compressor housing heats up so much that the compressor is damaged or that the lifetime of the compressor is reduced respectively.